Document DE 90 11 899 U1 as nearest prior art discloses an electromagnetic switching device and terminal-side accessories. A cable clamp block in a moulded case is provided as an accessory which can be joined in a form-fitting fashion with the supply- or the load-side terminal side of the switching device housing. To this end, the terminal sides of the switching device housing each show two groove-like guide and retaining recesses with undercut sections running perpendicular to the front side of the switching device housing, which can be brought into engagement and joined with the cable clamp block by means of two matching guide and retaining mouldings. As a further accessory, a protective cover made of moulded material is provided for protection against contact with current-carrying parts. The protective cover consists of two lateral protective walls, a front protective wall joining them and intermediate separating ribs connected to it. The protective cover can optionally be mounted directly to the terminal side of the switching device housing or to the cable clamp block. For fastening to the switching device housing, the protective cover is provided with guide and retaining mouldings on one front face which match the guide and retaining mouldings of the cable clamp block in position and shape and can be brought into engagement and joined with the guide and retaining recesses of the switching device housing. For fastening the protective cover to the cable clamp block, it has two lateral guide and retaining rails running perpendicular to the front side which can be brought into engagement and joined with matching guide and retaining recesses on the protective cover. The protective cover can be locked in a defined position by means of a locking hook formed in the protective cover. For adjusting the length of the protective cover to particular requirements, the protective cover exhibits parting lines running crosswise to the longitudinal direction of the cables.
By contrast, in the circuit breaker according to document DE 295 05 046 U1, a cable clamp block is screwed to the switching device housing. In attaching a protective cover to the cable clamp block, pairs of ledges provided on it, terminal-side grooves and outward-pointing L-shaped indentations cooperate with corresponding pairs of slots constructed on the front face of the protective cover and clamp ribs on the face and lateral, inward pointing retaining webs. Direct assembly of the protective cover to the switching device housing is not provided for.